Lighting for microgreens - not as complicated as you might think.
When I first started growing microgreens, my head was fully blown when it came to researching lighting options!
6 years on, and many different lighting trials later, I’m here to share my experience with you in this week’s blog post. Grab a cuppa.
If you’ve been reading my blog a while, you’ll know I like to keep everything in my microgreens farm as simple as possible. If something works well in the uncomplicated inexpensive way, then I’ll do it in the uncomplicated inexpensive way. And this definitely goes for my microgreens lights.
Microgreens don’t need many resources to grow well but light is something they DO need, so does need to be considered (unless you’re growing popcorn shoots that are only palatable when grown in the dark - one for another day!). All plants on Earth need light to photosynthesise and grow and microgreens are no exception.
What’s the best kind of light for growing amazing quality microgreens?
The short answer here is - SUNLIGHT! Nothing compares to the flourishing, leafy goodness you can grow under natural sunlight. And this doesn’t have to be direct sunlight, indirect and dappled sunlight works just as well (and usually better! - less wilting). Never have I grown peashoots more abundantly, sweet tasting and leafy as I did during the summers of growing them outside in my greenhouse. It’s tried and tested and it’s a free and renewable energy source.
Sadly however, the downside of using only natural sunlight to grow your microgreens commercially is it’s inconsistent throughout the year. Especially in the UK!
My grow room from May to September during the summers of 2017 and 2018 in Leeds, UK. Outside glass greenhouse, no electricity. Daylight was my sole lighting and the natural breeze through the door and windows sorted the airflow!
As soon as outside light levels reduce, your micros will start to grow slower, more leggy and have a paler colour, as they won’t be able to photosynthesise as effectively any more. And that’s where supplementary, artificial lighting can help us out.
Also, if you don’t have a greenhouse or poly tunnel or lots of bright windowsills, then you’ll have to use artificial lighting all year round for healthy, consistent crop production.
The minefield that is lighting options for microgreens!
If you’ve tried to research this topic at all, you might well have become as overwhelmed as I did when I first started looking. I was so baffled and indecisive that I didn’t even get any lights for the first 8 months of my business!
Over the years, and through experience, I’ve come to the following 2 conclusions when it comes to the lighting needs of microgreens:
1. Expensive, fancy grow lights work great and enable you to grow excellent quality microgreens.
2. Inexpensive, non-fancy lights also work great and enable you to grow excellent quality microgreens.
This can be a little controversial in indoor plant growing circles, but I’ve trialled several different types of lights over the years and, for the particular crops I choose to grow, any difference in crop growth was either non existant or negligable. Microgreens have short grow cycles and therefore don’t need a fancy light frequency and colour to get them to harvest stage.
My 3 criteria recommendations for your microgreens lights:
Choose a white light and ‘cool’ brightness of 6500K (this is daylight brightness so works well). Different coloured lights can also be used to grow microgreens such as red and blue light, but white lights are cheaper and work just as well.
Use LED lights rather than flourescents. For much more efficient energy use than anything else. Cheaper to run, better for the environment. LED’s use significantly less energy than flourescent lighting and last a really long time.
Lights that can be connected together from shelf to shelf on your grow racks are a huge bonus! It means you’ll need fewer power cables and the whole set up is much neater. Always ensure you don’t connect more together though than the manufacturer suggests.
Ultimately, any shop bought LED batons will enable you to grow great quality microgreens. And this is exactly what I used for the first 3 years of my business. The downside of these however was they were designed to be ceiling lights, so I had to wire a power cable to them myself so each light therefore had an individual cable plugged in. That’s 10 power cables per rack! It worked, but was bulky and not very convenient and it took me ages to do the wiring. And it definitely wasn’t the safest option (I’m not an electrician).
Luckily now there are lots of different cost effective options on the market, including slimline lights that can be daisy-chained together and can be bought easily in the UK. Hurray!
My current favourites, and ones I’ve been using in my farm for the past 3 years, are:
Barrina LED T5s (T5s and T8s just describes the diameter of the tube. T5s are skinnier than T8s)
PROS - lightweight, skinny, 8 can be connected together at once, low cost, grow great microgreens.
NOT-SO-PROS - they’re made in China and the connections feel quite cheap and flimsy (mine have never failed though). They’re usually supplied with a European plug so that needs to be changed for use in the UK. They’re not waterproof.
WHERE TO GET THEM IN THE UK - Lots of places online sell these. Also keep your eye on Grow Sow Greener’s lighting stock (coming soon!).
Kroptek LED Tube Series
PROS - great quality build, IP65-rated so fully waterproof and dust proof, can be linked together, grow great microgreens.
NOT-SO-PROS - the price. They’re over 3 times the price of the Barrinas - a big outlay if you’re just starting out.
WHERE TO GET THEM IN THE UK - Again the lovely lot at Grow Sow Greener will have these in stock shortly! Other than that, you’ll have to go to Kroptek directly.
BARRINA LED T5s - 120cm KROPTEK LED TUBES - 120cm
How much light and distance from your crops
Experiment with your light cycles in your own space. I go with an equal 12 hours on and 12 hours off light cycle. Plants need darkness in their grow cycle just as much as they need light, mostly to give them a rest from producing food through photosynthesis. Microgreens can stretch a little more in the darkness too, whilst they're searching for light, potentially increasing overall yield.
Two light battens per shelf is sufficient (going on 45cm depth shelves). Space them evenly. If you’re using wire shelving, they can easily be cable tied on.
Generally you'll want to space your shelving with an approximate 30cm gap between your light and the shelf. This will leave enough space for your taller crops to grow, such as peas, sunflower and wheatgrass, but is close enough to provide plenty of energy for healthy, robust plant growth. Even for shorter micros, my own shelves are set at this distance as it enables sufficient air flow around the crops.
Electrical Safety in your Grow Room
As a starter, and before growing any crops, make sure the electrical supply to your grow room is safe and in good working order. If you’re unsure get an electrictrian to check it all over for you.
Duty of care in your grow room:
1. Switch your lights off when watering.
2. General care and attention when watering your crops. Wipe up any spills immediately.
3. Consider installing shelf liners.
4. Consider using cable-tidies for all your electrical cables.
5. Don't overload plug sockets. Sockets in good working order in the UK can take up to 3000W in one socket. Don't exceed this. If using a plug adaptor, the flat gangway style ones are the best (either 4 or 6 plug spaces).
In conclusion, you don’t need specialist horticultural lighting to grow great quality microgreens in a small scale set up.
*Not to be missed this week:
If you want to have an up to date, UK-specific, comprehensive equipment list for your microgreens business, then this is included in just one of the Modules in my UK Microgreens Business Course.
The 11 Modules take you through all the elements you need to get set up, run and successfully scale your microgreens business to a size that suits you and your lifestyle. I teach a low tech system, that you can run from home and make a good living doing it.
It's a pretty fun way to spend your working life too!
Enrolment re-opens this Thursday 23rd February at 4pm :)
Click here to join the waiting list and be emailed when enrolment re-opens!
